1. Field of the Invention
The present invention relates to a die for press-molding glass optical elements such as gratings, light wave guides, hologram pickups and the like, and a production method for manufacturing glass optical elements using the die.
2. Description of the Related Art
Conventionally, optical elements having fine concave and convex patterns are manufactured by working photosensitive resin plates, resin molding or dry-etching glass plates (See, for example, JP-A SHO 54-110857 and JP-A SHO 55-57807).
Gratings made of photosensitive resin are easy to manufacture but have a disadvantage in that accuracy of fine patterns becomes worsened by deformation due to environmental changes such as temperature, humidity and the like. Further, resin gratings are apt to become scratched since the hardness of resin is not so high. Thus, it is difficult to obtain resin gratings having high accuracy and reliability.
In contrast to resin gratings, glass gratings have advantages in that they have sufficient hardness and high reliability against environmental changes. However, it takes an extremely long time to manufacture glass gratings by dry-etching and, thus, it is difficult to mass-produce those having the same configuration.